Display Data

1
Display Data

• PS.1.AC.4 Apply probability to real-world
  situation such as weather prediction, game
  theory, fair division, insurance tables, and
  election theory.
• Students will be able to construct a
• stem-and-leaf plot.

2
Stem-and-Leaf Plots

• Graphs and plots are often used to provide visual
  representations of the distribution of the data.
• One type of visual data display is the
  stem-and-leaf plot.
• The first step to construct this type of plot, is
  to divide the data into stems and leaves.
• The last digit of each number is referred to as
  the leaf, the remaining digits form the stem.

3
Stem-and-Leaf Plot Example
Cholesterol Levels

• This is the cholesterol level for twenty women on
  a magazine staff. Construct a stem-and-leaf
  plot.
• 185 234 208 197
• 259 177 192 188
• 208 200 215 199
• 209 234 208 146
• 216 201 232 186

Stems Leaves 14 6
15 16 17 7 18 5 6 8 19 2 7 9 20 0
1 8 8 8 9 21 5 6 22 23 2 4 4
24 25 9
4
Clusters, Gaps and Outliers

• Once you have put the data in a stem and leaf
  plot, you would be able to find some of the
  following
• A cluster is a group of data items that are close
  together.
• A gap is the space between clusters.
• An outlier is a number in the data set that is
  abnormally larger or abnormally smaller than the
  other data items.

5
Stem-and-Leaf Plot Example
Cholesterol Levels

• As you can see 146 is much less than the other
  data and 259 is much larger. These data items
  are considered to be outliers.
• There is a large cluster from 177 up to 216, and
  a small cluster from 232 to 234.
• There are three gaps, 146-177, 216-232 and
  234-259.
• The mode is 208.
• The median is 204.5.

Stems Leaves 14 6
15 16 17 7 18 5 6 8 19 2 7 9 20 0
1 8 8 8 9 21 5 6 22 23 2 4 4
24 25 9